Cam lock



May 7, 1940.

H. Z. BENTON CAM LOCK Filed Aug. 8, 1939 INVENTOR.

vPatented May 7, 1940 UNITED STATES PATENT OFFICE Name Plate &Manufacturing C0., Chicago, Ill., a corporation of Illinois ApplicationAugust 8, 1939, Serial No. 288,917

The invention herein disclosed relates to devices known as cam locks andemployed for securing in adjusted relation the so-called station yselecting cam-like levers used in radio tuning o apparatus.

Objects of the invention are to provide a device of the nature stated,which can be operated to release or to secure the so-called cams,without requiring the use of any tools; which when released, willlightlyl hold the cams in .adjusted relation, While permitting freeindependent adjustment voi other cams; which will secure the camswithout applying torque such as might have a tendency to displace orthrow them out of adjustment and which with all these desirablecharacteristics will be relatively inexpensive, consisting of but fewparts, be easily assembled and be relatively small and compact, so as toadd no objectionable weight or bulk to the radio tuning mechanism.

Other objects and the novel features of the invention arev set forth orwill appear in the following specilcation.

'I'he drawing accompanying and forming part of the specificationillustrates one commercial embodiment of the invention, but structuremay be modified and changed in various ways all vwithin the trueintentof the invention as hereinafter defined and broadly covered in theclaims.

Fig. 1 is a broken and part sectional plan view of one of the units inlocking position and with broken lines indicating movement of parts tothe unlocked position.

Fig. 2 is a broken cross-sectional view as on line 2--2 of Fig. 1.

Fig. 3 is a cross-sectional detail as on line 3-3 of Fig. 1.

' Fig.. 4 is a broken longitudinal sectional view on substantially theplane of line 4-4 of Fig. 1.

In the several views, a. shaft such as employed for tuning a radioreceiving set is indicated at 5, journalled in bearings 6. l, on asuitable base or supporting'structure 8. Such shafts are usuallyconnected with the condensers or other tuning means of a receiving setthrough aI suitable coupling (not shown) and usually are provided with aknob 9, or other manual means of adjustment, exposed atthe front of theinstrument panel, indicated at I0. f

.The various .station selecting cams may be of dierent sha-pes and arehere simply shown as levers II, I2, I3, I4, pivotally engaged over theshaft between pairs of clamping Washers I5, slidingly keyed on the shaftat I6, Figs. 3 and v4, and

the adjoining pairs separated by spacing wash- ,ers 17. v

Locking of the cam stack is effected in the present invention bystraight longitudinal thrust, free of any rotational or torquecomponent, by means 5 comprising relatively. fixed and slidable thrustsleeves I8, I9, interposed bowed leaf springs 20, and a surrounding ring2|, for compressing said springs to thrust the movable sleeve endwiseinto holding relation with the cam pack. 10

The thrust sleeves are in the nature of cages, socketed at 22, toreceive and position the ends of the bowed springs and the sleeve I8,which is xed to the shaft at 23, additionally has a ange 24, positionedas shown in Fig. 1 to serve as a stop 15 shoulder limiting the lockingmovement of the spring compressing ring 2|.

The locking and unlocking ring may be operated in various ways and it ishere shown as operated by a fork 25, pivoted on a stud 26, and carryingdiametrically opposite pins 21, entered in an annular groove 28, in thering. This fork is shown as having a lever extension 29, which mayproject through the case of the instrument or be otherwise accessiblylocated for convenient operation when setting the camsv to stationselecting posi-A tion.

The movable thrust collar I9, is shown as separated from the adjoiningcam securing clamp washer I5, by a spacing Washer 30, through which thelocking thrust is applied to the pack. A similar spacing washer 3|, isshown at the opposite end of the pack engaged by the adjusting nut 32,on the screw-threaded portion 33, of the shaft, said nut when adjustedbeing made fast by lock nut 3l. v

In setting up the unit, the nut 32, is usually adjusted to put thesprings under a slight tension, sc that when relieved of the compressiveaction of the surrounding ring as in Fig. 4, they will yieldingly holdthe cams lightly in various positions of adjustment. This tension may bejust sulcient to prevent the cams which have been adjusted from slippingout of position rwhile other cams are being set to desired stationselecting position. In this released relation, the control ring may restflat against the end flange 35, of the movable thrust sleeve as shown inFig. 4 and as indicated in broken lines in Fig. 1.

After adjustment of the cams is effected, the entire pack can besecurely locked without disturbing their relative positions by simplyshifting the handle 29, .from the released position indicated in brokenlines, Fig. 1 to the full line position. This simple movement shifts thecontrol ring 2|, up over the bowed springs 20, flattening them to anextent such as illustrated in Fig. 1, and causing them to elongatesuiciently to force the loose thrust sleeve against the pack with enoughpressure to hold the pack locked solidly on the shaft. In this lockedcondition, the entire assembly will turn free of any drag, since theshifter pins 26, ride loosely in the groove 28, as the control ringturns with the unit. The stop shoulder 24, of the xed sleeve may bepositioned to stop the ring just as it reaches or passes over the crestof the bowed springs, so that the tension of the' springs will beeffective to retain the control ring in this locking position. At anytime however, the pack can be instantly released for adjustment or otherpurposes and without any tools, by simple movement of the -lever fromthe full line to the broken line position, Fig. 1.

The device consists of but few and relativeliT small simple parts,inexpensive and easily assembled. The locking unit is of such size thatit can go into sets where small space is allowed for such a device. Thesockets in which the ends of the springs t are shaped to hold thesprings in their out-bowed relation between the collars. In theillustration, the hubs of the collars are shown as grooved at 36, inline with and in continuation of the retaining seats to more fully guideand hold the springs as they are flattened inward. The control ring isshown in Fig, 4, as bevelled at 31, in the direction of springcompressing movement to readily ride up over the bowed portions of thesprings and also to provide clearance for the springs in the openposition, Fig. 4.

Advantages of the invention may be more fully appreciated on consideringthat locking devices at present on the market require rotating against astop to lock and unlock, where the present invention enables locking andunlocking right at the tuned station, so as not to lose its identity inthe event it is desired to reset more accurately or to move to anadjacent radio channel. In using the end torque type lock, the stationsmay be retuned and in many cases, when once lost, cannot be easily foundagain, particularly by one not familiar with the scale calibrations and,finer adjustments of a receiving set. All such dimculties are avoidedwith the present invention.

What is claimed is:

. 1. In combination with a shaft and individually adjustable leverelements and clamp washers mounted thereon and constituting a cam pack,abutments on said shaft at opposite ends of said cam pack and means forapplying endwise locking pressure to said cam pack, comprising bowedleaf springs disposed longitudinally of the shaft and interposed at aposition between said abutments and means for applying straighteningpressure to said bowed springs to thereby elongate the same.

2. In combination with a shaft and a cam pack thereon, relativelyseparable abutments on said shaft and arranged to exert locking pressureon said cam pack, bowed leaf springs disposed longitudinally of theshaft and interposed between said relatively separable abutments andmeans for applying straightening pressure to said bowed springs tothereby elongate the same and effect relative separation of saidabutments.

3. In combination with a shaft and a cam pack thereon, thrust collars inlongitudinally separable relation on said shaft and adapted to applyendwise locking pressure on said cam pack, said thrust collars havingopposed seats, bowed springs having their ends entered 1n said seats anda ring between said thrust collars and movable over the bowed portionsof said springs for relatively flattening and elongating the same.

4. In combination with a shaft and a cam pack thereon, thrust collars inlongitudinally separable relation on said shaft and adapted to applyendwise locking pressure on said cam pack, said thrust collars havingopposed seats, bowed springs having their ends entered in said seats, aring between said thrust collars and movable over the bowed portions ofsaid springs for relatively attening and elongating the same and levermeans for shifting said ring in opposite directions.

5. A cam lock, comprising relatively separable shaft collars in opposingrelation and having aligned seats in the opposing faces of the same,bowed springs having their ends entered in said seats, a ring elementslidingly engaged with the bowed portions of said springs for effectingattening and elongation of the same and means for shifting said ringelement in opposite directions.

6. A cam lock, comprising relatively separable shaft collars in opposingrelation and having aligned seats in the opposing faces of the same,bowed springs having their ends entered in said seats, a ring elementslidingly engaged with the bowed portions of said springs for effectingattening and elongation of the same, means for shifting said ringelement in opposite directions, including a lever having relativelyrotatable engagement with said ring.

7. A cam lock, comprising relatively separable shaft collars in opposingrelation 4and having aligned seats in the opposing faces of the same,bowed springs having their ends entered in said seats, a ring elementslidingly engaged with the bowed portions of said springs for effectingflattening and elongation of the same, means for shifting said ringelement in opposite directions, said ring having a bevelled portionengageable with the bowed portions of the springs.

8. A cam lock, comprising relatively separable shaft collars in opposingrelation and having aligned seats in the opposing faces of the same,bowed springs having their.. ends entered insaid seats, a ring elementslidingly engaged with the bowed portions of said springs for effectingattening and elongation of the same, means for shifting said ringelement in opposite directions, said ring having an external annulargroove and said shifting means having pin elements engageable in saidgroove.

9. In combination, a shaft, a cam pack thereon, relatively separablethrust collars bearing endwise on said cam pack, bowed springs engagedbetween said relatively separable thrust collars and exerting a lightspring pressure to lightly hold the elements of the cam pack in theunlocked condition of the parts and a ring slidable over the bowedportions to effect relative separa tion of said thrust collars and heavyendwise locking pressure 0n said cam pack.

10. In combination, a shaft, a cam pack thereon, relatively separablethrust collars bearing endwise on said cam pack, bowed springs engagedbetween said' relatively separable thrust collars and exerting a lightspring pressure to lightly hold the elements of the cam pack in theunlocked condition of the parts, a ring slidable over the bowed portionsto' eiiect relative separation of said thrust collars and heavy endwiselocking pressure on said cam pack and an end abutment on the shaft fortaking-the combined thrust of the cam pack and locking means described,said abutment being longitudinally adjustable on the shaft forpresetting the position of parts to determine the initial holdingtension of the bowed springs.

11. In combination, a shaft, a cam pack thereon, relatively separablethrust collars bearing endwise on said cam pack, bowed springs engagedbetween said relatively separable thrust collars and exerting a lightspring pressure to lightly hold the elements of the cam pack in theunlocked condition of the parts and a ring slidable over the bowedportions to eiect relative separation of said thrust collars and heavyendwise locking pressure on said cam pack and lever means having arelative rotatable engagement with said ring for shifting the same.

12. In combination, a shaft, a cam pack thereon, relatively separablethrust collars bearing endwise on said cam pack, bowed springs engagedbetween said relatively separable thrust collars and exerting a lightspring pressure to lightly hold the elements of the cam pack in theunlocked condition of the parts and a ring slidable over the bowedportions to eilect relative separation of said thrust collars and, heavyendwise locking pressure on said cam pack and stop means for limitingthe movement of said ring.

13. In combination, a shaft, a cam pack thereon, relatively separablethrust collars bearing endwise on said cam pack, bowed springs engagedbetween said relatively separable thrust collars and exerting a lightspring pressure to lightly hold the elements of the cam pack in theunlocked condition of the parts and a ring slidable over the bowedportions to eiect relative separation of said thrust collars and heavyendwise locking pressure on said cam pack, one of said collars having astop ange engageable by said ring.

14. In combination, a shaft, a cam pack thereon, relatively separablethrust collars v bearing endwise .on said cam pack, bowed springsengaged between said relatively separable thrust collars and exerting alight spring pressure to lightly hold the elements of the cam pack inthe unlocked condition of the parts and a ring slidable over the bowedportions to effect relative separation of said thrust collars and heavyendwise locking pressure .on said cam pack and means for stopping saidring in position substantially at or over the crest of said bowedsprings for effecting the holding of said ring in such position by saidsprings.

15. In combination, a shaft, a cam pack thereon, relatively separablethrust collars bearing endwise on said cam pack, bowed springs engagedbetween said relatively separable thrust collars and exerting a lightspring pressure to lightly holdthe elements of the cam pack in theunlocked condition of the parts and a ring slidable over the bowedportions to effect relative separation of said thrust collars and heavyendwise locking pressure on said cam pack, one of said collars having astop shoulder limiting the movement of said ring to a positionsubstantially at the crest of the bowed springs.

16.l A cam lock, comprising oppositely disposed relatively separablethrust applying shaft collars provided with aligned seats in theopposing faces of the same, outwardly bowed springs interposed betweensaid thrust collars and having their ends engaged in said seats, aspring contracting ring slidingly engaged over the intermediate bowedportions of said springs and means for shifting said ring in oppositedirections.

IEIAROLD Z. BENTON.

